Monsters of the Abyss
by StoryMakerr014
Summary: One week after Operation MI, a surprised and unexpected death leaves the naval district reeling. Facing an unknown and deadly enemy, the fleet girls must exert all efforts in order to defeat it. But as they will soon discover, it is just the beginning. And they will need a new weapon. A weapon long thought to be just a myth.
1. Chapter 1

Prologue: A New Enemy

 _Annihilate._

The creature swam slowly within the depths of the ocean, its limbs propelling the massive body it possessed. Baleful orange eyes locked on a dark speck in the water's surface, prompting it to curl its lips into a snarl as it drew closer.

 _Annihilate._

It was never hungry. It never needed to eat. Its sole mission was simply to destroy; to kill. Much like its predecessors, its masters created it with a single purpose in mind: eradication.

The creature uttered a low growl that made the other ocean denizens scatter in abject terror. Its shape alone made it a terrifying monster to behold. From its four clawed arms to the axe-shaped crest protruding from its bony forehead, the creature looked very much like an incarnation of nightmare itself.

 _Annihilate._

It kicked its powerful legs to propel itself up. The dark speck has already moved away, but the monster was still fast enough to catch up with it. Soon, its teeth would sink into its prey's fragile body.

Soon, it would kill.

* * *

Ooi let out an irritated sigh as she cruised across the water. The sky was clear and the ocean was still, sparking in the sun. But despite this, there was a storm brewing inside her. It was supposed to be her date with Kitakami, but an order from Nagato ruined her plans for tonight.

And she thought she could finally have that kiss she had been dying to have ever since they met.

Scowling, she increased her speed to catch up with Kitakami and the rest of their squadron. Ever since Operation MI, the Admiral had been sending out recon teams farther out to the ocean. Most of the Abyssals had already withdrawn after their defeat, but the commander didn't want the fleet to lower their guards. A counter-attack was still possible, and they needed to be vigilant at all times.

But that didn't mean they had to ruin her date! Of all the days they could have chosen to send them out, it just had to be today. Couldn't she get some quality time with her beloved every once in a while?

Grumbling to herself, she focused her attention on the mission. Better to finish this as quickly as possible then. That way, the two of them could return home and have their date.

Ooi looked around. Fubuki and Mutsuki had decided to go ahead of them as forward observers in case an Abyssal group attacks. Takao and Atago were both nowhere to be seen. But she could still detect them in her radar. Which meant she and Kitakami were the only ones around in these parts.

Talk about a blessing in disguise!

"Hey, Kitakami!" she hollered. Her other half glanced back, a puzzled look crossing her beautiful face.

"Ooicchi?"

She grinned and sped up. She was still far away; a couple of hundred meters, at least. But that didn't matter. Distances were nothing to her undying love for Kitakami. Even if it was on the other side of the ocean, she would reach her.

"It seems we are the only ones in here!' Ooi called. A hundred and fifty meters, and gradually decreasing. Silently, she cursed her gear for not having the speed of a destroyer's.

"Yes, I can see that! What about it?" Kitakami frowned, an action that made Ooi giggle. She always found her frown very cute.

"Well, I was just thinking if you want to hold hands?" Ooi's grin widened. "I don't want us to get separated when it's just the two of us."

A hundred meters. Almost there!

Kitakami immediately blushed and slowed down a bit. "Oh! I... ah..." she stammered. "Well... sure. Why not?"

Ooi squealed in delight and burst forward, spraying water on all sides. She whooped as she drew closer to Kitakami, her one and only Kitakami, stretching out her arms to reach out to her.

And in her excitement, she didn't notice how the water rippled behind her beloved. She didn't see the dark shadow in the surface grew steadily larger as something sinister rose up. She didn't see the two orange orbs that didn't belong to any sea creature on this planet.

What she only saw was a clawed arm reaching up to pull down Kitakami by her legs, and her terrified expression as a monstrous head emerged in a spray of water before biting down on her shoulder. What she only heard was the thunderous explosion of Kitakami's gear, and her own scream as her beloved was dragged down below the ocean.

And what she only felt was terror and despair as a foe more terrible than any Abyssal she had ever faced before took the life of the very first and last girl she had ever loved.

* * *

"What happened?"

With hurried footsteps, Nagato strode along the hallway, Mutsu trailing behind her. The Secretary Ship was just discussing their next plans with the Admiral when Mutsu barged inside looking as if she had come across an Abyssal fleet.

"Kitakami was sank—"

"What?!" Nagato immediately halted, staring with a shocked expression at her assistant. "How? There should be no Abyssal fleet within the area we sent them!"

"I don't know the details. Ooyodo simply told me that Recon Team 6 returned without Kitakami, " Mutsu shook her head as they continue, albeit with greater speed than before.

Despite the urgency of the situation, Nagato remained calm. This was not the first time they had lost a ship, and she had learned how to control her emotions during times like this.

And yet...

"Too sudden," she muttered. "We've only just recovered from Operation MI, but now..."

Nagato sighed. They should have already expected this. The Admiral was right; an Abyssal counter-attack did happened. And now, they had lost another ship girl. She should have been more careful.

It didn't take long for the two of them to reach the docks where almost the entire fleet was gathered around a shell-shocked Ooi who was sitting on the ground and hugging her knees.. Mutsuki was beside her, and Fubuki as well, providing emotional support. Not surprising, considering they experienced what Ooi did when destroyer Kisaragi was sank.

The rest of the girls were in a somber mood. To lose another fleet girl was a huge blow to their morale, especially since it was only a week after their major victory at Base MI. Even Kongo was not in her usual jovial mood, her eyes clouded by sadness.

Nagato stopped just outside the circle. Immediately, all eyes turned toward her, some of which were red from crying. Kitakami was well-loved by everyone, and her destruction left a gaping hole in their hearts.

"Nagato-san," said Fubuki softly. She didn't salute, but Nagato let that pass. There was something more important than formalities right now.

Taking a step toward Ooi, Nagato knelt in front of her. "Ooi."

The light cruiser didn't answer. She was trembling, and she kept whispering unintelligible words under her breath. Strange thing was she possessed no sign of damage—an unusual sight for someone who had encountered an Abyssal fleet.

"Ooi, answer me," said the battleship with more force, lacing her voice with a commanding tone. When Ooi still didn't respond, she sighed and asked to no one in particular, "Can anyone tell me what actually happened?"

There was a brief silence, then Takao spoke from the left. "Permission to speak, Secretary?"

"You don't need to ask, Heavy Cruiser Takao. You're the team leader, after all." There was an edge in Nagato's voice as she subtly reminded the ship girl what her responsibility was.

Takao winced then continued. "It was around 1100—"

"Cut to the chase, Takao! What happened?"

The girls stiffened as Nagato's voice rose, almost in a shout. She never raised her voice before except during battles, and even she herself was surprised. What surprised the secretary ship more, however, was Fubuki answering the question.

"It's my fault, Nagato-san!" Her voice trembled slightly. "If only I had not convinced them to let me and Mutsuki scout, we would have never leave Kitakami and Ooi alone. I'm sorry, Ooi! I'm sorry, everyone!"

Murmurs went from the crowd. They didn't blame the destroyer, nor could they even if they wanted to. It could have happen to any of them at any time, whether they were alone or not, and they all knew it. Such was the fate of a fleet girl.

"It's not your fault, Bucky," Kongou sniffed, rubbing the girl's head.

"No, because it's mine," Takao lowered her head, ashamed. "If only Atago and I had just stayed close, we could have prevented the attack. I'm sorry."

"Enough," said Nagato as she finally regained her composure. Despite her own frustration, it would not do any good if they start blaming each other for what had already happened. "There's no one at fault. Nobody knew this was going to happen, and we didn't expect a counter-attack so soon. I don't want any of you blaming another one, am I clear?"

"Yes, Secretary Nagato!" They all said.

Sighing, Nagato stared at Ooi more intently. The light cruiser was still shaking, and her eyes bore a terrified expression. Her lips were trembling while she continued to whisper inaudibly. Kitakami's death must have been too violent for her to be traumatized like this.

PTSD was not unusual for a ship girl. Infused with the spirits of the actual ships they were named for, many of them still possessed memories of the events they had experienced; Nagato herself still had an aversion to nuclear weapons, and Akagi, as she had displayed during Operation MI, was still guilty about her previous incarnation's failure during the Battle of Midway. And though they all tried to forget their tragic fate by focusing on the present, neither of them could could completely erase it from their memories.

After a while, Nagato finally stood up and crossed her arms. "What was the size of the Abyssal fleet that attacked them?" she glanced at Takao. Suddenly, the heavy cruiser became hesitant, and Nagato noticed Fubuki's expression growing more serious.

"Well, that's the thing, Secretary Nagato," Takao replied slowly. "We don't know."

She sounded embarrassed and troubled at the same time. Arcing an eyebrow, Nagato asked, "You don't know? What do you mean by that?"

"Well..." Takao shifted uneasily. "We don't know because we didn't picked them up on our radar. And when we asked Ooi about it... she..." Her voice trailed off, almost as if she was reluctant to say what she intended to say.

"What? What did Ooi tell you?" Nagato pressed on.

Takao was silent at first. Then after a deep breath, she spoke.

"Ooi said it was a giant monster."

There was a stunned silence. At the word "monster", Ooi began to rock back and forth, her shaking becoming more violent. And this time, they could finally hear her mutterings.

"It ate her... It ate her... It ate her..."

The air suddenly felt cold, and Nagato shivered. The way Ooi said it sent chills down the hardened ship girl's spine. It was the first time she had heard about an Abyssal eating a ship girl.

"Wait. Aren't all Abyssals considered as monsters?" Someone wondered aloud. It sounded like Akatsuki.

There were murmurs of agreement. However, Nagato was still doubtful. It didn't match with what they knew of Abyssal behaviour and attack patterns.

"What do you think?" It was Mutsu whispering next to Nagato. "Could it be a new class?"

The battleship shook her head and answered with a sigh of exhaustion. "I don't know. But if it really is, then we have to develop a way to counter their stealth technology. I don't like the way they could just sneak up undetected on our radar."

Nagato sighed. She thought they already had a slight advantage against the Abyssals after the success of Operation MI, but it seemed their enemies had quickly adapted. Now, they were back to zero.

"We can't defeat it..." Ooi suddenly whimpered. She looked up, and Nagato saw fear and despair in her eyes. "We can't defeat a monster!"

Nagato stared down at her. She could understand the girl's feelings, but it still irked her that she could give up so easily. "Hast thou exerted all possible efforts?" she quoted their tenet to pacify Ooi and also to make sure the rest of the fleet would not start losing morale.

"You don't understand," Ooi whispered tearfully. "We can't fight a monster."

Nagato sighed again. This was getting nowhere. "If you don't mind, Ooi, can you tell us what this monster looks like?"

She knew it would be hard for the light cruiser to relive the painful memory, but they needed details. If there was a new Abyssal class of ship, they had to know everything there was to know about it.

Unfortunately, the terrified ship girl remained silent. When it was clear she wouldn't divulge any useful information, Nagato shook her head and turned around. "Everyone, back to your posts. It seems Ooi here won't be able to help us. Fubuki, Mutsuki, take her back to the dorms. Drag her if you have to."

The fleet girls saluted, thoufh half-heartedly. As they were about to disperse, however, footsteps echoed behind Nagato. It stopped, then a voice said, "Did I hear it correctly? Ooi said 'monster'?"

All of them gasped. It was the Admiral.

"Admiral?" Nagato was stunned. He rarely left his office except during ceremonies. What was he doing here?

"Don't look so surprised," the man chuckled. "I still have to go outside, right?" Then in a serious voice, he turned toward Ooi. "I heard what happened from Ooyodo. Tell me, is it true? You saw a monster?"

Despite herself, Ooi couldn't ignore the highest ranking officer of the naval district. Her voice shaking, she answered, "Y-yes."

For a moment, the Admiral looked troubled. "Can you tell me what it looks like?" he said gently.

Ooi sniffed. "Well, I didn't see all of it. But it was large and scary. Kind of similar to those monsters from the movies. Its arms were long, and there were four of them. Plus, it has this huge axe-shaped crest on its head and... Admiral?"

Very few things could shock Nagato, and one of those was a horrified Admiral. As soon as Ooi mentioned about the bony crest, the man had turned pale until it looked like his blood was completely drained.

In a quiet voice, he asked, "Axe-shaped crest? Are you sure about this?"

Ooi nodded. "Yes, sir."

The man let out a shaky breath. His hands trembled for a moment, but he soon regained his composure. Whatever Ooi said, it was clear it had troubled him greatly. But why?

His expression grim, the Admiral spoke.

"Nagato, come to my office at once. The rest of you, wait at the auditorium."


	2. Chapter 2

Chapter 1: Admiral's Order

The silence that pervaded the auditorium only served to emphasize the gloomy atmosphere of the naval district.

Despite almost every ship girl gathered in one place, there was little to no conversation happening. Most of them were either fidgeting in their seats, or glancing at the door that led to the command center where Nagato was currently having a meeting with the Admiral. All were awaiting an explanation about this new and deadly foe Ooi had encountered.

Already, rumors were starting to spread. Some theorized it was a new class of Abyssal specifically created to hunt down and eat ship girls. Others thought it could actually be a new enemy that was not even related to the Abyssals, and the creature had emerged to conquer both Earth and where ever dimension Abyssal came from. Whatever the monster was, it had shaken up the whole district.

Speaking of the creature, not much was known about it. Ooi was too traumatized to even describe the monster properly. And since she had only seen the arms and part of the head, those information were not enough. Apparently though, the Admiral somehow knew what it was if his reaction to Ooi's description was anything to judge by.

For her part, Fubuki hoped everything would be alright. They were still recovering from Operation MI, and an enemy that could sink a torpedo cruiser in an instant did not bode well for them. They did not know what Abyssals were and where they came from. But a new kind of enemy? That was a bit too much.

"I wonder how goes the meeting? It's been almost an hour now."

Fubuki glanced at Mutsuki. The other destroyer had a forlorn expression, and the reason was quite obvious; Kisaragi's sinking was similar to how Kitakami sank today, so she could sympathized with Ooi. Both of them could.

"I don't know. Let's just wait for them to finish. I'm sure the commander has a plan."

"But they're taking too long!" Beside them, Yuudachi pouted. She yawned, then lay on her side, taking up the entire spaces of three empty chairs. Despite her remodeling, she still retained a part of that laid-back attitude of hers.

"It shouldn't be too long now," said Fubuki reassuringly despite her own concerns. It was not unusual for the Secretary Ship to spend a long time discussing important matters with the Admiral. However, this was different. As the minutes dragged on, Fubuki couldn't help but feel her anxiety rose. Just what was this new enemy that it was taking the Admiral an hour to tell Nagato about it?

They didn't have to wait long. Just as Fubuki felt herself drifting to sleep, the sound of footsteps echoed far ahead. She snapped into attention just as Nagato appeared with a serious expression, making her way to the podium. The battleship stopped, then placed her hands on either side of the board. The entire fleet immediately stood up and saluted.

For a moment, there was only silence. Though the destroyers were situated near the back, Fubuki could still see Nagata's face. And she didn't like how her eyes scanned them as if this would be the last time she would address the entire fleet.

"Attention to all ship girls. I have an important message from the Admiral."

This may be the last time she would see any of them.

That thought ran across Nagato's mind as she swept her gaze at the crowd. Her knees were still weak from her recent discovery, but she did not let that show. The last thing she needed was for the girls to see her in a vulnerable state. It would greatly affect their morale if one of the Big Seven displayed fear and despair, especially with their new enemies.

Kaijus. That was what the Admiral had called them. At first she thought he was joking; it sounded like a term from those 1950s monster films Mutsu loved to watch. But then he showed archived footages and photos, and her skeptism instantly vanished.

When the Admiral told her the history of these monsters, her legs almost turned to jellies. Giant beasts hundreds of feet tall capable of leveling cities and resistant, but not invulnerable, against nuclear weapons. They came from an alternate dimension as an extermination force to wipe out any threat on a planet, possessing a hive mentality so that every time one of them fell, their successors would have the information needed to adapt to whatever method their enemy used.

300 hundred years ago, Humanity had once waged war with these otherworldly beasts. And for a time, they were losing. But someone thought of a new weapon, and the tide quickly turned. The war lasted almost a decade until the threat was ultimately ended. Or at least, they thought they had ended it. Apparently, the Kaijus were back for revenge. When she had asked the Admiral about the weapons, however, the man didn't elaborate on the matter. Instead, he just gave her an order for the fleet.

Naturally, she had to comply. But that didn't mean she liked it; what the Admiral wanted for them to do seemed too cowardly for her.

Gripping the edges of the podium until her knuckles were almost white, Nagato began. "Attention to all ship girls. I have an important message from the Admiral." She paused briefly, making sure their eyes were on her. Many were worried, but some were curious. When their entire attention was focused on her, she continued. "Since most of you already know what happened this morning, I'll go straight to the point."

She took a deep breath then said, "The Admiral has ordered us… not to engage the monster when we see it."

The silence that followed was so deep she could hear the faint cries of a seagull from a mile away. Everyone was frozen on their seats, unmoving as a statue. Then in a heartbeat, almost as if someone had pressed the play button, the entire auditorium burst into chaos.

"That's stupid!"

"Do not engage? We are ship girls! We can take on a monster especially at night!"

"This is an insult to our pride! What is the Admiral thinking?!"

"An idol never retreats from a fight!"

"That's unfair, poi! We also want revenge for Kitakami!"

The bombardment of protests made Nagato sighed. Just as she had expected, they would not accept the Admiral's order very easily. She could understand them, and even she wanted to tell the commander how they should not flee like cowards but exert all possible efforts to overcome their foe. Sadly, his order was clear.

Amidst the clamor, she noticed that Fubuki was the one of the few not participating. To her amazement, the special type destroyer remained silent after her announcement, and her expression was one of quiet acceptance.

Nagato felt a little bit of her worry vanished. She had realized that the girl was not complaining because she trusted the Admiral. And there's no reason for them not to do the same thing. In all of their operations, the commander had not let them fail. What right did they have to doubt him in this kind of situation then?

Understanding crossing her face at last, the battleship took another deep breath and roared, "Silence!"

Everyone stopped shouting at once. Many seemed to had realized what they did and lowered their heads in shame. To question an admiral was widely considered as an insult, and a disgrace for a ship girl.

"Have you all forgotten who we are?" Nagato glowered, her voice magnified in the silence. "We are ship girls. We exist to take back the seas, and also to obey the Admiral's orders. If we cannot trust him, how are we suppose to trust ourselves to finish our mission?"

Her words carried the desired effect. Murmurs of apology swept through the crowd. Near the front seats, she saw Kongo wiping a few tears from her eyes. Aside from Fubuki, she also didn't protest at the commander's decision.

"Secretary, you cannot blame us for questioning the order." Zuikaku stood up wearing a fierce expression. "We never retreat from a fight unless we cannot win it. And we always do! We took down many Abyssals before even though we are outnumbered. Surely, a single sea monster won't be any different!"

"But it is different, Aircraft Carrier Zuikaku," countered Nagato. "I've talked with the Admiral and he said they can't be harmed by normal weaponry. One of the only few ways to kill them is to use a nuclear bomb." She paused to let that last sentence sink in.

It did. There were gasps from the crowd, and a few even turned pale at the revelation. Despite the incident had already happened almost 400 years ago, many still remembered the horrors of Hiroshima and Nagasaki.

"That's impossible! Secretary Nagato, if only a nuclear weapon could kill them then that means they are stronger than the Abyssals! Just what are they?" Zuikaku looked whiter than a ghost when she asked that.

The battleship was about to answer, but to her surprise, Kirishima beat her to it.

"Kaiju. That's the name, isn't it?" Her voice was soft, almost a whisper, but everyone heard her.

Nagato regarded her curiously. "How do you know this?"

Kirishima adjusted her eyeglasses then answered, "I've read about them in the library. Back then I thought they were just myths…"

"Apparently, they are not." Nagato scanned the crowd and addressed them once more. "Yes, we are dealing with a monster from the abyss. A creature that can't be killed by normal methods. Therefore, until we find a way, we must avoid direct confrontation. If you encounter it during missions, run. That is the commander's order, and we must follow it to the letter. Am I clear?"

The girls shifted uneasily on their feet, but nonetheless replied with an affirmative, "Yes, ma'am!"

"Good. You're all dismissed."

With that, Nagato left the podium.

* * *

Admiral Yamamoto stared outside the window with a troubled expression, pondering over the recent events. Being near the sea, his office overlooked the vast expanse of water that stretched for miles. The gentle lap of the waves on the concrete pier usually calms his mind, but now it only reminded him of the death of another ship girl.

Kaiju. He had hoped he would never utter those word in his 48 years of existence. He had only heard stories of those monsters from his grandfather, who in turn had also heard it from his grandfather. Back then, he simply considered it as old tales meant to scare away children whenever they refuse to sleep. But now it seemed the story had became a reality.

Of course, he had long expected something like this to happen. Before he took command of his own naval district, and in fact before he was officially promoted to an admiral, he was briefed on theories and speculations regarding the origins of the Abyssals. One topic was often brought up, and that was the kaijus. There had been rumors way back in his thirties that since the monsters had failed, the Abyssal race was created to replace them.

He didn't bother paying attention to it at that time, and now his girls were paying the price. If only he had listen to the constant reminders of his colleagues, Kitakami would still be around. But he dismissed what he once thought were ramblings of old men, and now he couldn't bring back the past.

There was still a way to ensure history wouldn't repeat itself, however.

Yamamoto turned away from the window and looked at the telephone. He could still fix this. They still have a fighting chance. All he needed to do was make a call. If the letter he had received 2 months ago was right, Japan had finally recreated three of them.

His face set in a determined expression, the Admiral strode over to his desk and dialled a number. After a few rings, someone picked up and he said in an instant, "This is Admiral Yamamoto. I need to speak with the Marshall."


End file.
